1. Field of the Invention
The present invention relates to a private wireless network, and more particularly to a system and a method for providing information about a location of a private wireless network subscriber.
2. Description of the Related Art
A private wireless network (also referred to as a Private Mobile Network) generally provides a mobile station (MS) of a private wireless network subscriber with a mobile communication service in a restricted zone such as a specific building, that is, on a premise. As one example of a private wireless system for providing such a mobile communication service, an “InfoMobile” system having been developed by Samsung Electronics Co., Ltd., Korea can be cited. This InfoMobile system provides a variety of wireless calls, data services and Internet Protocol (IP) terminal services together with Private Automatic Branch Exchange (PABX) functions.
In the private wireless network as mentioned above, the mobile station must necessarily notify the private wireless system of its location, slot mode, power-up/-down state, etc., in order to be serviced with an incoming call. To realize this, the private wireless network has a location registration function for managing states and situations of mobile station's movement in real time as in a Public Land Mobile Network (PLMN). Even without making a call, the mobile station occasionally executes location registration, that is, a work for notifying the private wireless system of its location and state, according to which the notified locations and states of the mobile station are managed as databased location-registration information in a Home Location Register (HLR) Visitor Location Register (VLR) of the private wireless system. The location registration is commonly subdivided into “power-up registration”, “power-down registration”, “timer-based registration”, “distance-based registration”, “zone-based registration”, “parameter-change registration”, “order registration”, “implicit registration”, “traffic channel registration” and so forth.
The “power-up registration” is location registration in which a mobile station, not having been in use, notifies the private wireless system of its current location and state when its power is turned on. The “power-down registration” is location registration in which power-down of a mobile station is notified to the private wireless system when its power is turned off. The “timer-based registration” is location registration which is periodically carried out in order that a mobile station may be provided with the normal wireless communication service. The “distance-based registration” is location registration which is carried out when a mobile station becomes removed from the last location-registered spot by a certain distance. The “zone-base registration” is location registration in which a new location zone is registered with the private wireless system when the location zone of a mobile station is changed. The “parameter-change registration” is location registration which is carried out when a user intentionally changes parameters stored in a mobile station, such as phone numbers or the like. The “order registration” is location registration which is executed by compulsory order of abase station demanding location registration of a mobile station. The “implicit registration” is location registration which is implicitly carried out at an outgoing call or an incoming call response of a mobile station. The “traffic channel registration” is location registration which is implicitly carried out when a location zone of a mobile station is changed through handoff, etc., during a call. Using the location-registration information according to the above-mentioned location registration, the private wireless system can judge whether it is possible to make a call to a specific subscriber or to provide the relevant subscriber with its service or not.
On the other hand, a location of a mobile station may be known as the unit of a base station on the basis of the location-registration information as stated above. Taking notice of this point, some PLMN service companies are providing location tracking services for allowing to find out a location and a moving route of a subscriber by indicating, on an electronic map, a location of a base station with which the latest location of a mobile station has been registered, that is, a base station which is considered closest to the relevant mobile station.
Such a location tracking service, however, is not put in practice in the private wireless network which uses the location-registration information only for judging whether it is possible to make a call to a specific subscriber or to provide the relevant subscriber with its service or not. Also, even the location tracking services being put in practice in the PLMN do not provide a subdivided location of a subscriber within a service zone covered by each base station, but find out a subscriber's location only as the unit of a base station. In order to enable a subscriber's location to be more precisely tracked within a service zone covered by a base station, it must be required either that a mobile station has a GPS (Global Positioning System) receiver so as to notify a base station of its location information received from a GPS satellite, or that it not only executes location registration whenever it moves over a certain distance, but also it receives, from a base station with which the mobile station has registered its location, latitude and longitude information of the relevant base station, calculates its location on the basis of the received information, and then notifies the network of the calculated location.